From: Andrew Bardsley <Andrew.Bardsley@arm.com>
Date: Thu, 30 Oct 2014 04:18:24 +0000 (-0500)
Subject: cpu: Fix barrier push to store buffer when full bug in Minor
X-Git-Tag: stable_2015_04_15~163
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=536c72333f71f6e816d4b5e95e39754638bd76ea;p=gem5.git

cpu: Fix barrier push to store buffer when full bug in Minor

This patch fixes a bug where a completing load or store which is also a
barrier can push a barrier into the store buffer without first checking
that there is a free slot.

The bug was not fatal but would print a warning that the store buffer
was full when inserting.
---

diff --git a/src/cpu/minor/lsq.cc b/src/cpu/minor/lsq.cc
index 0a473af89..cae0d3666 100644
--- a/src/cpu/minor/lsq.cc
+++ b/src/cpu/minor/lsq.cc
@@ -1370,9 +1370,13 @@ LSQ::findResponse(MinorDynInstPtr inst)
         /* Same instruction and complete access or a store that's
          *  capable of being moved to the store buffer */
         if (request->inst->id == inst->id) {
-            if (request->isComplete() ||
-                (request->state == LSQRequest::StoreToStoreBuffer &&
-                storeBuffer.canInsert()))
+            bool complete = request->isComplete();
+            bool can_store = storeBuffer.canInsert();
+            bool to_store_buffer = request->state ==
+                LSQRequest::StoreToStoreBuffer;
+
+            if ((complete && !(request->isBarrier() && !can_store)) ||
+                (to_store_buffer && can_store))
             {
                 ret = request;
             }